The so called 软席 or soft seat is a word contrast to 硬座(ying4 zuo4) or hard seat. The difference between the two is comparable to that of, for example, first and economy seating on many international flights or first and second class seats on trains in Western Europe. On trains in China, a soft seat is more spacious and comfortable than a hard seat. Accordingly, a soft seat ticket costs more than that of a hard seat.
软席候车室 is an designated waiting room in a train station for those who have soft seat tickets. It is seperated from 候车室, the main waiting room in a station.